Trenchless cable pulling systems and trenchless pipe bursting/pipe replacement systems are a fast growing standard in the pipe replacement industry. Such “trenchless” systems require only two pits to be dug, one at each end of the pipe to be replaced. One end of a pulling cable is attached to the front end of a bursting pipe head device, and the other end is threaded through the existing pipe from an entry point accessible in the entry pit and provided to a pulling apparatus located in the exit pit. The pulling apparatus then pulls the cable and the attached bursting pipe head device through the existing cable, typically by a hydraulic mechanism which may be electrical or gas-powered. The bursting pipe head device bursts or fractures the existing pipe as it is pulled through, and brings with it replacement or product pipe attached at the back end of the bursting pipe head device. Pat. Nos. US Patent Application Publications US 2002/0081154; US 2006/0088384; US 2008/0181728; US 2104/0241812; and U.S. Pat. Nos. 6,305,880; 6,357,967; 6,672,802; 6,913,091; 6,799,923; 7,284,624; 8,414,225; 8,540,458; 8,702,349; 8,784,009; and 8,979,435 are representative of the state of the art.
There is an on-going desire to improve these trenchless pulling systems, including to: (1) minimize the size of the pits to be dug; (2) reduce the weight and size of the pulling apparatus; (3) provide maximum flexibility for hydraulic power sources; (4) enhance cable fidelity and minimize breakage or binding during the cable pulling process; (5) increase the facility and ease for engaging cable with and disengaging cable from both the pulling apparatus and the bursting head; (6) increase the facility and ease for cable disengagement for large and small pipe diameter bursting heads; (7) increase the facility and ease of maintaining and using small and large pipe diameter bursting pipe head devices; and (8) managing pipe extraction in small diameter pipe replacement applications.
The present disclosure describes improvements in cable pulling systems and methods and trenchless replacement pipe pulling systems and methods that overcome deficiencies in the systems and methods of the prior art.